Image from Teichlebewesen.

The Phylum Annelida is represented by two classes*: Polychaeta and Clitellata. Polychaetes are typically marine, although almost 170 species have been reported from fresh waters. Most of these species are representatives of typically marine families, and it is unclear at this time how many represent freshwater occurrences vs. actually reproducing freshwater populations of polychaetes. In North America, 33 species of fresh- and ground-water polychaetes from 10 families are reported by Glasby & Timm (2008).

In constrast, the Class Clitellata are best represented in continental habitats, both terrestrial and freshwater. The class is represented by three distinct subclasses: Oligochaeta, Branchiobdellae, and Hirudinea. Oligochaetes are burrowing deposit-feeders. There are about 5000 currently recognized species worldwide, of these c. 1100 occur in freshwater habitats. 238 species (75 genera, 13 families) have been recorded from North America (Martin et al., 2008). There are about 700 species of the Class Hirudinea, and the majority of these occur in fresh waters. These are the leeches, which are ectoparasites, scavengers, and predators of vertebrates and invertebrates. Around 80 species of leeches are known from North America. The Branchiobdellae are weird little worms, all commensal on freshwater crustaceans. About 150 species are known from North America.

The Phylum Annelida is zoologically significant as the “segmented worms.”

* Not counting the enigmatic “phyla” Echiura and Sipuncula.

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Bibliography

• Zhang, Z.-Q. 2011. Animal biodiversity: An introduction to higher-level classification and taxonomic richness. Zootaxa 3148: 7-12. [Available online]
• Govedich, F.R., B.A. Bain, W.E. Moser, S.R. Gelder, R.W. Davies & R.O. Brinkhurst. 2010. Annelida (Clitellata): Oligochaeta, Branchiobdellida, Hirudinida, and Acanthobdellida. [in] J.H. Thorp & A.P. Covich (eds.). Ecology and Classification of North American Freshwater Invertebrates, 3rd edition: 385-436.
• Sket, B. & P. Trontelj. 2008. Global diversity of leeches (Hirudinea) in freshwater. Hydrobiologia 595: 129-137. [Available online]
• Martin, P., E. Martinez-Ansemil, A. Pinder, T. Timm & M.J. Wetzel. 2008. Global diversity of oligochaetous clitellates (”Oligochaeta”; Clitellata) in freshwater. Hydrobiologia 595: 117-127. [Available online]
• Glasby, C.J. & T. Timm. 2008. Global diversity of polychaetes (Polychaeta; Annelida) in freshwater. Hydrobiologia 595: 107-115. [Available online]
• Brusca, R.C. & G.J. Brusca. 2003. Invertebrates, 2nd edition. Sinauer Associates, Inc., Sunderland, Massachusetts. 936 pp.
• Smith, D.G. 2001. Annelida (Polychaetes, Aeolosomatidae, aquatic oligochaetes, Branchiobdellida, leeches). Pennak's Freshwater Invertebrates of the United States, 4th edition: 269-325.
• Gelder, S.R. 1999. Zoogeography of branchiobdellidans (Annelida) and temnocephalidans (Platyhelminthes) ectosymbiotic on freshwater crustaceans, and their reactions to one another in vitro. Hydrobiologia 406: 21-31. [Available online]
• Gelder, S.R. 1996. A review of the taxonomic nomenclature and a checklist of the species of the Branchiobdellae (Annelidae: Clitellata). Proceedings of the Biological Society of Washington 109(4): 653-663.
• Holt, P.C. & B.D. Opell. 1993. A checklist of and illustrated key to the genera and species of the Central and North American Cambarincolidae. Proceedings of the Biological Society of Washington 106(2): 251-295.
• Underhill, J.C., W.D. Schmid & D.E. Gilbertson. 1982. Taxonomic Keys to the Common Animals of the North Central States, exclusive of the parasitic worms, terrestrial insects, and birds, 4th edition. 205 pp.
• Stimpson, K.S. & D.J. Klemm. 1982. A guide to the freshwater Tubificidae (Annelida: Clitellata: Oligochaeta) of North America. U.S. Environmental Protection Agency. 61 pp. [Available online]
• Klemm, D.J. 1982. Leeches (Annelida: Hirudinea) of North America. U.S. Environmental Protection Agency. 177 pp. [Available online]
• Amin, O.M. 1981. Leeches (Hirudinea) from Wisconsin, and a description of the spermatophore of Placobdella ornata. Transactions of the American Microscopical Society 100(1): 42-51. [Available online]
• Hiltunen, J.K. & D.J. Klemm. 1980. A guide to the Naididae (Annelida: Clitellata: Oligochaeta) of North America. U.S. Environmental Protection Agency. 47 pp. [Available online]
• Foster, N. 1972. Freshwater polychaetes (Annelida) of North America. U.S. Environmental Protection Agency, Biota of Freshwater Ecosystems Identification Manual 4. 15 pp. [Available online]
• Moore, J.P. 1959. Hirudinea. [in] W.T. Edmondson (ed.). Ward & Whipple Fresh-Water Biology, 2nd edition: 542-557.
• Hartman, O. 1959. Polychaeta. [in] W.T. Edmondson (ed.). Ward & Whipple Fresh-Water Biology, 2nd edition: 538-541.
• Goodnight, C.J. 1959. Oligochaeta. [in] W.T. Edmondson (ed.). Ward & Whipple Fresh-Water Biology, 2nd edition: 522-537.
• Pennak, R.W. 1940. Ecology of the microscopic Metazoa inhabiting the sandy beaches of some Wisconsin lakes. Ecological Monographs 10(4): 537-615. [Available online]

Student Essays

• "Oligochaeta: Biological Indicators" by Sheila Behling (BIOL/WATR 361, Fall 2013 )
• "Diversity of Freshwater Subclass Oligochaeta in Wisconsin" by Alyssa Roberts (BIOL/WATR 361, Fall 2013 )
• "Feeding habits of Hirudinea" by Andrew Shuster (BIOL/WATR 361, Fall 2013 )
• "Ecology of Branchiobdellida (Annelida: Clitellata) in North America" by Josh Schulze (BIOL/WATR 361, Fall 2012 )
• "Hirudo medicinalis and Hirudinaria manillensis feeding physiology and medical use" by Zach Kleemann (BIOL/WATR 361, Fall 2013 )
• "The Aquatic Oligochaete Tubifex tubifex as a Water Quality Indicator" by Hayley Templar (BIOL/WATR 361, Fall 2012 )
• "Hirudo medicinalis: The Revival of the Medicinal Leech" by Lindsey DeVault (BIOL/WATR 361, Spring 2015 )

Web Pages

• Animal Diversity Web
• Center for Annelida Resources
• Fauna Europaea
• Freshwater Animal Diversity Assessment
• Integrated Taxonomic Information System
• Tree of Life
• WikiSpecies
• Wikipedia
• World Polychaeta Database
• World Register of Marine Species